Exhaust steam injector



NQV. 4, 1941. L E ET AL 2,261,853

EXHAUST STEAM INJECTOR Filed July 23, 1940 J2me .Qme :7? 7 1 41 Patented Nov. 4, 1941 EXHAUST STEAM INJECTOR Richard David Metcalfe and James Croxon Metcalfe, Romiley, England, assignors to Davies & Metcalfe Limited, Romiley, England, a British company Application July 23, 1940, Serial No. 347,070

' In Great Britain August 5, 1939 1 Claim.

This invention relates to exhaust steam injectors and is concerned with the valves which close the conduit by which exhaust steam is supplied to the injector for the purpose of cutting oil such supply and for preventing any blow back from the injector along the exhaust steam supply branch. Hitherto two separate valves have been employed, opening in opposite directions, one valve being entirely automatic whilst the other is opened by a piston and steam pressure and closed by a spring.

The object of the present invention is to provide an improved valve arrangement for controlling the admission of exhaust steam and for preventing blow back from the injector into the exhaust pipe.

The invention comprises the arrangement of a double type of valve at the inlet to the injector to control the inflow of exhaust steam thereto, the valve spindle being at right angles to the axial line of the injector nozzles, one of the valves (that is the upper valve) being larger than the other, a spring to hold the Valves closed, and a piston beneath the valve stem which is raised to open the valves when exhaust steam to work the injector is available.

The accompanying drawing is a longitudinal section of an exhaust steam injector constructed in one convenient form in accordance with this invention.

a indicates the branch by which exhaust steam is admitted to the injector. b indicates the supplementary live steam inlet nozzle, the steam from which assists in increasing the injector delivery pressure beyond what is obtainable by the use of exhaust steam only to operate the injector. c indicates the passage through which live steam throttled down to low or about atmospheric pressure is admitted to the injector to work the same when there is no exhaust steam available at the branch a. Water enters the injector between the cones d and e and some of the exhaust or low pressure steam enters the nozzle system between the cones e and ,f. g is the combining nozzle, and h the delivery nozzle.

The exhaust steam supply to the injector is admitted by the double beat valve comprising the two interconnected valve portions 11 and 7' which seat upon seats is and m disposed with their axis at right angles to the axis of the cones and nozzles b, d, e, f, -g and h. The valve 2 is larger than the valve 7' and a spring n acts to assist the valve 1' to remain closed upon its seat It against the action of any blow back from the injector towards the inlet a for exhaust steam.

It will be appreciated that when exhaust steam is not available and the injector is working with live steam throttled down to a low pressure, there may be a tendencyfor the steam to blow back towards a from the live steam inlet at c.

The valve spindle 0 at its lower end enters a casing p in which is a piston q which is exposed at its underside to the pressure in a passage 1' leading from a control valve fitting 8.

When there is exhaust steam available, that is. when the engine from which the exhaust steam is obtained is functioning and receiving live steam in the engine valve chest, there is steam pressure in the passage T which causes the lifting of the piston q and so of the valve spindle o and valves i and y to allow the exhaust steam to pass to the injector, but when there is no exhaust steam available, that is when there is no live steam in the engine valve chest, there is no steam pressure in the passage r and the valves 2' and :i close due to their weight assisted by the spring n, so cutting oil the exhaust steam inlet branch from the injector.

It will be seen that with our improvement, the one double beat valve serves to admit exhaust steam to the injector, to prevent blow back from the injector when working with live steam and to out 01f the exhaust steam when the injector is not at work.

As the exhaust steam supply is made available past both valves i and a in parallel, each valve can be of much less size than with present arrangements. Also the piston q which opens the valves i and 9' can be made of much less size than with the present arrangement because it has only to overcome the pressure applied to the difference in area of the two valves i and 7'.

Our arrangement simplifies and cheapens the valve arrangement and gives a more reliable and durable mechanism.

What we claim is:

In an exhaust steam injector, the arrangement of a double type of valve at the inlet to the injector to control the inflow of exhaust steam thereto, the valve spindle being at right angles to the axial line of the injector nozzles, one of the valves being larger than the other, a spring to hold the valves closed, a control valve fitting, a passage leading from said fitting, and a piston beneath the valve stem which is raised to open the valves by the pressure in said passage when exhaust steam to work the injector is available.

RICHARD DAVID METCALFE. JAMES CROXON METCALFE. 

